Carlo Leoni (13 March 1955, Rome) is an Italian politician.
After a long time as an activist and director of the Partito Comunista Italiano (PCI) and of the Democratici di Sinistra (DS), he became a deputy in the Italian Chamber of Deputies in 1996, and was re-elected to that role in 2001 and 2006.
In the XIV Legislatura he became the DS's capogruppo on the Commission on Institutional Affairs of the Chamber and a member of the Bicameral Anti-mafia Commission. On 4 May 2006 he was elected vice-president of the Chamber of Deputies.
Following the 4th Congress of the DS, which sanctioned the birth of the Partito Democratico, Leoni left the DS and joined the Sinistra Democratica.